1. The invention relates to a method for producing a cooled cast part produced by a lost-wax process for a thermal turbo machine.
1. Cast parts for thermal turbo machines are produced using known casting processes. Casting furnaces for such casting processes are known, for example, from publications EP-A1-749 790, U.S. Pat. Nos. 3,763,926, or 3,690,367. The casting molds usually are provided in the form of a wax model. A process for producing a complex part of a gas turbine using a casting mold is known, for example, from publication U.S. Pat. No. 5,296,308.
2. Depending on the specific embodiment, a core is placed into the wax model. This core contains the structure of the cavity that forms a specific cooling structure inside the casting part. In these casting parts, a wax seat must be applied between the wax model and the core in order to prevent the slip, that in its dry form forms the casting mold, from penetrating into the intermediate space. The wax seal is applied by hand onto a step adjoining the core. This step has the ultimate purpose of holding a cooling plate. The cooling plate is soldered or welded onto the step and is used, by means of cooling holes, for impact-cooling the platform located below it. In order to prevent leakages of cooling air, the surface of this step should be smooth. But this is in contradiction with the applied wax seal that, after casting, results in an accumulation of material above the step. In order to get closer to the goal of a smooth surface of the step, an additional process step, for example grinding or eroding, is necessary.
1. The invention is based on the objective of creating a method for producing a thermally loaded and cooled cast part for a thermal turbo machine by using a known casting process, whereby the casting mold of the cast part is produced with a wax model and a ceramic core, and the subsequent production steps are simplified and optimized.
2. According to the invention, this objective is realized with a method for producing a cooled cast part for a thermal turbo machine by using a known casting process and a casting mold. The casting mold is produced by using a wax model and a core located inside the wax model. A step is located immediately next the core for the attachment of a cooling plate to the finished cast part. Prior to the production of the casting mold of the cast-part between the wax model and the core, the wax seal is applied to only one shoulder that is located above the step in the direction towards the side of the core.
3. This provides the advantage that even during the casting process it can already be prevented that rough areas are created on the step that would result in a leakage of the cooling air at the cooling plate. The material that is created during the casting process as a result of the wax seal and the shoulder can be ground off or removed using another appropriate manner with a uniform process step without forming rough areas on the step. A cooling plate can be soldered to this step without any additional process steps.